Extension cord



Jan. 3, 192s. 1,655,263

, H. H. FROST EXTENS I ON CORD Filed Dc. 1. 1924 .Hen-ferr if. .2U-a5 fy f Patented Jan. 3, 1928.

UNITED STATES PATENT OFFICE.

HERBERT H. FROST, 0F CHICAGO, ILLINOIS, ASSIGN OR, BY MESNE ASSIGNMENTS,T0

CHICAGO TELEPHONE SUPPLY COMPANY, `O14" ELKI-IART, INDIANA, A. CORPORA-'rien or DELAWARE.

Application filed December In using a loud speaker in connection with aradio receiving set, it is citen desirable to have the loud speaker in aditerent rooml or at some point relatively distant trom the setitsel'it. Usually, as a matter ot practical expedience, the receivingapparatus is generally kept in some out-oI-the way spot where -it is notapt to be disturbed. Such a place, however, may not be suitable :torlistening in to the music, speeches, or what-l ever the nature of thematter may be which is being broadcasted. Unless means'are provided,therefore, to permit of the loud speaker functioning at a place which ismore desirable roin the listeners standpoint, the inconveniences o theroom where the set is actually located must be borne even though a moredesirable one isavailable.

'lo eliminate this linconvenience to the radio listener, l provide anextension cord having a plug at one end which is adaptable forconnection to the radio set, and a novel jack at the other end to whichthe loud speaker may be connected. The type or jack and plug used andthe manner in which they are connected, are illustrated in the accom.-panying drawing. 1n the drawing:

Figure 1 is a plan view showing the connection of the plug of the loudspeaker to the novel jack ot 4my invention;

Figure 2 is a sectional -view showing the manner in which the conductorsleading to the plug and jack respectively are connected;

Figure 3 is another sectional view taken at right angles to the view ofFig. 2 ot' the plug and jack used in my invention showing, however, ingreater detail the manner of constructing the jack;

Figure 4 is a plan view of the tip spring used in connection with thejack;

Figure 5 is a side elevational view of the sleeve to which the end ofthe extension cord is secured; and

Figure 6 is an end view of the sleeve.

One of the novel features of my invention consists in the provision of asuitable sleeve or housing 1 for the jack 8. The sleeve 1 is preferablymade of a piece of ibre tubing although I may use what is commonly knownand marketed under the trade naine of bakelite, or the like, and haspressed into one of its ends, a washer or ring 2 of the same material.An aperture 3 is EXTENSION' CORD.

1, 1924. Serial No. 753,032.

thus provided in the end of the housing through which the cord 4 may befreely adi mitted for connection with the separate contact members ofthe jack 8. In order to make tlie'sleeve as attractive as possible, Iturn down the end ot the sleeve and the Washer to a smooth curve andfinish.

The opposite end of the sleeve 1 is threaded to receive the mountingplateor block 5. A liuted or knurled flange the outer diameter of whichis substantially equal to the outer diameter of the sleeve 1, is formedon the block or plate 5 and is provided for manually turning the plate 5to thread it into or out or" the sleeve 1. An adjusting tliimble 7having a hexagonal head and a threaded sleeve integral therewith snuglylits through the mounting screw 5. The threads on the sleeve are adaptedto be received by the threads in the aperture contained in the leg ofthe jack trame 8. By

tightening the lhexagonal nut oi' the adjustin'g thimble 7 the threadedsleeve portion will draw the jack frame 8 against the end of themounting screw 5 and thus keep it in a relatively fixed position.

Threaded into the base portion of the jack frame 8 are the screws 11.Between the heads of the screws 11 and the jack frame A8, thev contactand insulating members of the jack yare firmly held together. Theseconsist of a ground spring, 12 which makes electrical lcontact with thejack lframe, of insulation strips 18, the tip spring 14, an insulationstrip 15, and the metal Washers 16. Insulation bushings 17 separate thetip spring 14 from the screws 16. A novel means of connecting theextension cord 4 to the ground spring 12 and the tip spring 14 isprovided in the use of the contact sleeves 18. The spring 14 togetherwith one of the sleeves 18 connected thereto, is shown in plan in Figure4. The tip spring 14 has a sharp bend 19 for engaging with the groove 2Oin the tip of the contact member 21. In the body portion of the spring,openings 23 are provided into which the insulating bushings 17 arefitted to insulate the spring 14 from the .screws 11. An extendingterminal member 24 integral with the body 22 serves as a means forconnecting it with the contact sleeve 18.

Contact sleeve 18 is illustrated in greater detail in Figures 5 and 6 inwhich the Y or the like.

spring terminal member 24 is shown as tting into a diagonal slot 25.These contact sleeves may be stoel: items and a similar contact sleeveis connected to spring 12.V

Each sleeve has a flat side tace 26 and an eccentriclongitudinal'opening 27 vforming a socket. The flat tace 26 is suitablefor mounting thereon a contact of the spade type and the longitudinalopening 27 is suitable for inserting therein a contact ot the tip type.By means ofthe clamping screw 23 either type of contact may be firmlysecured to the sleeve. The opening or socket 27 is oiiset from thecenter ot the relatively circular end of the sleeve 1S in order toprovide sutilcient stock for the screw 28 so that it can clamp theterminal. This dispositionoic the fiat clamping face and the eccentricsocket-permits reduction in the size of they sleeve 1 considerablythereby making the jack as a Whole more compact and more pleasing inappearance.

Y AThe jacket which encloses Vthe extension cord 4 terminates in a cord44 Which is Wound around the insulating members 13 in order to take thestrain off of the flexible conductors Which are connected to the sleeves18.

The plug 30 which is connected to the opposite end of the extension cord4 is identical With the plug 10 shown in Figures 2 and 3. This plugconsists of a sleeve portion or housing 31 which may also be made offibre', One of the ends of the sleeve 31 is down turned so as to formthe opening 32 to permit the connecting cord 33 to be led therethrough.The cord 33 is provided With Contact tips 34 Which are adaptable forinsertion into the sleeve members 35 and 41. Knurled thumb screws 36serve as means for holding the tips 34 in fixed position in thesesleeves. The sleeve 41 is rigidly secured in the member 37 of which thecontact member 39 forms a part. The* sleeve -35 is insulated from themember 37 by the strip of insulation material V38. The electricalconnection between the sleeve 35 and the contact member 21 is made bymeans or" the metal strip 42 and-a central needle,V (not shown), Whichare rigidly connected to both. The insulating lWasher 43 and -a suitablesleeve o' insulation separate the contact y members 2l and 39 from eachother.

The method ot using my extension cord may be brielycdescribed asfollows: A suitable place for listening in is first determinedvupon.When this is done the plug 10 of the loud speakeris connected to thejack 9 tolwhich the extension cord 4 is secured. The cord is then ledback romrthis point to the receiv-V ing set Where it isconnected tothelset by means ot' the plug 30 thereby completing the circuit between theloud speaker and the receiving set. n

I do not intend to be limitedl to the de-y tails shown and described.-

Iclaim: *Y In electrical connecting means, a tubular casing of`electrical insulating material having an opening through one end toaccommodate an Aelectric cord, a mounting block removably secured in theother end of the casing, a jack including a mounting frame disposedWithin the casing and having an angularly disposed leg seatin on theinner face of the block, a. thimble aving a head on` itsrouter endandextending through the block, said thimble being threaded through theleg ot the jack frame and securingvit to Y' the block, and a resilientycontact member carried by and electrically insulated from said trame,said member being disposed for contact with the terminal element of aplug shank inserted throuUh thev thimble. Y

In Witness Whereoi?, I hereunto subscribe my name this 26 dayofNovember, 1924.

: HERBERT H. FROST.

